Means for tightening current supply plastes on electrodes in open or closed type electric furnaces



June 25.. 1968 F.-w. KAMPMANN ETAL 3,390,221

"BANS FOR TIGHTENING U RENT 5U Y PLATES 0N ELECTRODES IN Q OR CLO TYPE ELECTRIC NACES Filed June '1964 United States Patent ABSTRACT OF THE DISCLOSURE Current supply plates for the electrode for an electric furnace are clamped to the outer surface of the electrode by a circular thrust collar. The electrodes are elongated with the upper ends movably supported from a stationary support structure in a circumferential array about the electrode. Cotter keys inserted between each of the current supply plates and the thrust collar urge the sides of the current supply plates into firm contact with the electrode without imposing any longitudinal loads upon the clamping structure. The thrust collar may be advantageously provided by a circular'pipe circulating a cooling fluid. Saddle-shaped sections within the thrust collar are aligned with tapered links upon the supply plates to facilitate engagement of the cotter keys.

- The present invention is concerned with means for tightening current supply plates on electrodes in open or closed type electric furnaces.

It is always rather difficult to supply current to the electrodes of electric furnaces. Usually, power is supplied to the electrodes through current supply plates adjoining the electrodes in radial relationship, the current supply plates being caused into contact with the electrode or electrode shell under contact pressure variable according to operational requirements. Cotters, thrust bolts or hydraulic or pneumatic means are used to produce the contact pressure, whilst e.g. a rope collar or generally a collar having a box-like cross-sectional area is provided to receive the reaction pressure.

The present invention is based on the observation that substantially more favorable conditions can be created for smaller expense and provides a thrust collar comprising one or more pipes radially spaced from and encircling the electrode and allotted means applying the contact pressure to the current supply plates.

More especially, the thrust collar of this invention comprises at least one endless pipe bent so as to form a closed collar encircling the electrode, a saddle-shaped structure mounted on the inside surface area of the thrust collar, allotted to each current supply plate and designed to support the thrust collar on a nose disposed on each current supply plate, a pressure receiving ledge fastened to the current supply plates so as to be in opposite relationship to the saddle-shaped structure and spaced therefrom, and a cotter applying pressure to each current supply plate and forced into the space left between the saddle-shaped structure and the pressure receiving ledge.

Each endless pipe allotted to the thrust collar is provided with a cooling water inlet socket and a cooling water outlet socket and with a parting disk disposed therebetween.

The thrust collar is shown diagrammatically in the accompanying drawing in which:

FIG. 1 is a cross-sectional view of the electrode and a top plan view of the thrust collar encircling the electrode 3,390,221 Patented June 25, 1968 "ice FIG. 2 is a longitudinal section of the electrode taken along line IIlI and a cross-sectional view of a thrust collar comprising one pipe;

FIG. 3 is a longitudinal section of the electrode taken along line III-III and a cross-sectional view of a thrust collar comprising two pipes.

As shown in FIG. 1, the electrode 1 is concentrically surrounded by a collar comprising a thick-walled pipe 7 bent so as to form a plane circle, the two pipe ends being welded together in abutting relationship after one end thereof has been closed by the insertion of a parting disk 13. On either side of parting disk 13 pipe 7 is provided with a pipe socket, of which socket 11 is the cooling water inlet and socket 12 the cooling water outlet.

As shown in FIG. 2, which represents a section of FIG. '1 taken alOng line III-III, eyed fishplates are provided which flexibly suspend the current supply plates 2 from bearing 3 in block 4 which in turn is fastened to a fixed structure 5, such as a building structure. To each current supply plate 2, there is allotted a link 6 tapered in downward direction with respect to the electrode axis and serving as a pressure receiving means adjoining the base of the pressure applying means, i.e. cotter 10, advantageously designed as a gib key. On being tightened, the bed of cotter 10 transmits the reaction pressure to the saddle-shaped structure 8 welded on to pipe 7 serving as the thrust collar. The contact pressure exerted by the cotter on the pressure receiving means 6 and hence on the current supply plate 2 can be regulated by appropriately fastening or loosening cotter 10.

Cantilevers 9 disposed at current supply plates 2 provide the support receiving saddle-shaped structures 8 and the allotted thrust collar, which can be removed by loosening cotter 10, slightly lifting and turning the collar in its plane until saddle-shaped structures 8 are positioned approximately in the center between two adjacent current supply plates. The collar can then be lowered.

The thrust collar may also be designed so as to comprise two or more pipes. FIG. 3 shows an exemplary embodiment comprising two pipes 7 and 7 held in position by modified saddle-structures 8. In sectional FIG. 3, the visible cooling water outlet socket allotted to pipe 7' is defined by reference numeral 12. The parts not referred to correspond to the parts shown in FIG. 2.

The thrust collar consists of antimagnetic steel so as to keep electric losses low.

It is mentioned that individual structural parts may require electric insulation depending on the design of the whole apparatus.

The thrust collar of this invention for use in open or closed type furnaces, e.g. calcium carbide furnaces, offers various advantages over conventional means. Primarily, the Weight is substantially inferior to or in other words less than the weight of cast structures. Furthermore, each pipe of the thrust collar represents a single and smooth cooling water cycle having a constant cross-sectional area. The cooling water can therefore be caused to flow at a rate sufiiciently high to ensure good heat transfer data and small temperature difference between cooling water inlet and outlet. As a result thereof, the pipes are subjected to minor internal soiling, and cleansing operations are less frequently required. The space demands are so small that charging devices can be employed in open furnaces equipped with the present thrust collar which may also be used in closed furnaces with low base support.

We claim:

1. A means for tightening current supply plates on electrodes in open and closed type electric furnaces, the said means consisting substantially of a cooled thrust collar allotted to each electrode and having adjustable structural parts applying contact pressure in radial relationship with respect to the axis of the electrode and concentrically surrounding the electrode, the said thrust collar comprising at least one endless pipe bent so as to form a collar; a saddle-shaped structure allotted to each current supply plate, mounted on the inside of the said collar and seated on a cantilever which is connected in stationary relationship to the said current supply plates; a pressure receiving ledge fastened to the said current supply plates so as to be in opposite relationship to the saddle-shaped structure and spaced therefrom; a pressure applying cotter forced into the space left between the saddleshaped structure and the pressure receiving ledge, said thrust collar comprising two endless pipes having a cooling medium inlet socket and a cooling medium outlet socket allotted to each pipe, and a parting disk inserted between said sockets in respective pipes.

2. A means for tightening a plurality of current supply plates, which are pivotally secured to a stationary constructional part and associated in encircling relationship to electrodes for use in open and closed type electric furnaces, the tightening means being formed substantially of a cooled circular thrust collar for each of the electrodes and of adjustable structural parts applying contact pressure in radial relationship with respect to the axis of the electrode and concentrically surrounding the electrode, the said thrust collar being comprised of at least one endless bent pipe; a saddle-shaped structure associated to each current supply plate, mounted on the inside of the said collar and seated on a centilever fast with the said current supply plates; a pressure-receiving ledge arranged to be in opposite relationship to and spaced from the saddle-shaped structure and to be fast with the said current supply plates; and a pressure-applying cotter seated in the space left between the saddle-shaped structure and the pressure-receiving ledge.

3. A means for connecting current supply plates to an electrode for use in an electric furnace comprising a plurality of elongated current supply plates disposed about the circumference of said electrode, a stationary support structure disposed about the circumference of said electrode abovesaid current supply plates, motion permitting connecting means supporting the upper ends of said current supply plates from said support structure, ledge means projecting outwardly from said current supply plates in. a substantially circular array about the circumference of an electrode, a circular thrust collar resting upon said ledge means and disposed about said current supply plates, cotter means inserted between each of said current supply plates and adjacent portions of said thrust collar, the portions of said supply plates and said thrust collar contacted by said cotter means being constructed and arranged to become intimately wedged in firm contact therewith, and said cotter means being inserted into firm contact between said contacting portions of said current supply plates and thrust collar whereby said current supply plates are each clamped into secure contact with the surface of said electrode.

4. A connecting means as set forth in claim 3 wherein said thrust collar comprises a circular pipe having saddleshaped sections connected within it to provide surfaces for contacting said cotter means.

5. A connecting means as set forth in claim 4 wherein said portions of said current supply plates contacting said cotter means comprise tapered links connected to the outside of said current supply plates opposite said saddle-shaped sections on said thrust collar.

6. A connecting means as set forth in claim 5 wherein said cotter means comprise cotter keys inserted between each of said saddle sections and said tapered links.

References Cited UNITED STATES PATENTS 2,135,408 11/1938 Moore 1316 2,632,780 3/1953 Whitehouse 1316 FOREIGN PATENTS 122,034 1/1919 Great Britain.

BERNARD A. GILHEANY, Primary Examiner. H. B. GILSON, Assistant Examiner. 

